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Copper
) is a chemical element with the symbol Cu ( ) and atomic number 29. It is a ductile metal with excellent electrical conductivity, and finds extensive use as an electrical conductor, heat conductor, as a building material, and as a component of various alloys. Copper is an essential trace nutrient to all animals including humans. It is found primarily in the bloodstream, as a co-factor in various enzymes, and in copper-based pigments. However, in sufficient amounts, copper can be poisonous and even fatal to organisms. /> Biomedical applications * As a biostatic surface in hospitals, .Bacteria will not grow on a copper surface because it is biostatic. Copper doorknobs are used by hospitals to reduce the transfer of disease, and Legionnaires' disease is suppressed by copper tubing in air-conditioning systems. * Copper-62-PTSM, a complex containing radioactive copper-62, is used as a Positron emission tomography radiotracer for heart blood flow measurements. * Copper-64 can be used as a Positron emission tomography radiotracer for medical imaging. When complexed with a chelate it can be used to treat cancer through radiation therapy. Biological role include oysters, beef or lamb liver, Brazil nuts, blackstrap molasses, cocoa, and black pepper. Good sources include lobster, nuts and sunflower seeds, green olives, and wheat bran.]] Copper is essential in all plants and animals. Copper is carried mostly in the bloodstream on a plasma protein called ceruloplasmin. When copper is first absorbed in the gut it is transported to the liver bound to albumin. Copper is found in a variety of enzymes, including the copper centers of cytochrome c oxidase and the enzyme superoxide dismutase (containing copper and zinc). In addition to its enzymatic roles, copper is used for biological electron transport. The blue copper proteins that participate in electron transport include azurin and plastocyanin. The name "blue copper" comes from their intense blue color arising from a ligand-to-metal charge transfer (LMCT) absorption band around 600 nm. Most molluscs and some arthropods such as the horseshoe crab use the copper-containing pigment hemocyanin rather than iron-containing hemoglobin for oxygen transport, so their blood is blue when oxygenated rather than red.[http://www.ocean.udel.edu/horseshoecrab/funFacts.html Horseshoe Crab Fun Facts] NOAA and Univ. of Delaware It is believed that zinc and copper compete for absorption in the digestive tract so that a diet that is excessive in one of these minerals may result in a deficiency in the other. The RDA for copper in normal healthy adults is 0.9 mg/day. On the other hand, professional research on the subject recommends 3.0 mg/day.National Research Council. Copper. In: Recommended Dietary Allowances. Washington, D.C.: Food Nutrition Board, NRC/NAS, 1980: 151-154. Because of its role in facilitating iron uptake, copper deficiency can often produce anemia-like symptoms. In humans, the symptoms of Wilson's disease are caused by an accumulation of copper in body tissues. Toxicity Thirty grams of copper sulfate is potentially lethal in humans . The suggested safe level of copper in drinking water for humans varies depending on the source, but tends to be pegged at 1.5 to 2 mg/L . The DRI Tolerable Upper Intake Level for adults of dietary copper from all sources is 10 mg/day . In toxicity, copper can inhibit the enzyme dihydrophil hydratase, an enzyme involved in haemopoiesis . Symptoms of copper poisoning are very similar to those produced by arsenic. Fatal cases are generally terminated by convulsions, palsy, and insensibility. In cases of suspected copper poisoning, Ovalbumin is to be administered in either of its forms which can be most readily obtained, as milk or whites of eggs. Vinegar should not be given. The inflammatory symptoms are to be treated on general principles, and so are the nervous. A significant portion of the toxicity of copper comes from its ability to accept and donate single electrons as it changes oxidation state. This catalyzes the production of very reactive radical ions such as hydroxyl radical in a manner similar to Fenton chemistry. This catalytic activity of copper is used by the enzymes that it is associated with and is thus only toxic when unsequestered and unmediated. This increase in unmediated reactive radicals is generally termed oxidative stress and is an active area of research in a variety of diseases where copper may play an important but more subtle role than in acute toxicity. An inherited condition called Wilson's disease causes the body to retain copper, since it is not excreted by the liver into the bile. This disease, if untreated, can lead to brain and liver damage. In addition, studies have found that people with mental illnesses such as schizophrenia had heightened levels of copper in their systems. However it is unknown at this stage whether the copper contributes to the mental illness, whether the body attempts to store more copper in response to the illness, or whether the high levels of copper are the result of the mental illness. Too much copper in water has also been found to damage marine life. The observed effect of these higher concentrations on fish and other creatures is damage to gills, liver, kidneys, and the nervous system. It also interferes with the sense of smell in fish, thus preventing them from choosing good mates or finding their way to mating areas. . See also References Further reading * *Current Medicinal Chemistry, Volume 12, Number 10, May 2005, pp. 1161-1208(48) Metals, Toxicity and Oxidative Stress External links Category:Copper Category:Chemical elements Category:Dietary minerals Category:Metallic elements